* Supports new GNTP (Growl Notification Protocol) for cross-platform compatibility* Supports images in notifications* Supports playing sounds when notifications are received* Supports sending callbacks when a notification is clicked/closed* Keyboard shortcuts for closing last notification and closing all notifications* History feature that records all notifications* Missed notifications summary* Bonjour support enables automatic discovery of other Growl instances on your network (PC or Mac)* Forward notifications to iPhone, email, and Twitter* Notification forwarding can now be configured on a per-application or per-notification basis* Improved UI with smoother notification fades and animation* Integrated with tons of apps* Available in multiple languages* Command line interface for sending notifications from scripts* Libraries available for sending notifications from a variety of programming lanugage* Complete developer SDK for creating custom displays* 100% free and open-source